Refrigerating apparatus



' Aug 10, 1937. w. H. TE TER 9 2,089,630

REFRIGBRATING APPARATUS Filed July 19, 1934 7&1

24 s'uz 40 35 Patented Aug. 16, v.

. ammo Fries Wilford E. Teeter, Dayton, Ohio, omignor to General MotorsCorporation, Dayton, Ohio, a corporation or Delaware Application July19, recs, soul at. 730,031

This invention relates to refrigerating apparatits and more particularlyto a valve for compressors for refrigerating app It is an object of theinvention to provide a valve for passing refrigerant therethrough in onedirection only, which is not only reliable, quick and positive in itsaction, but whichis also free from the production of noise in itsoperation.

It is also an object to provide a valve foring of refrigerant inone'direction only, which comprises really a pair of valves, one ofwhich opens to a small degree very slightly before the other one opens,.to avoid a sudden change in 1 pressure between one side of the valveand the other and to thus eliminate noise in opening and closing. 1

Further objects and advantages of thepresent invention will be apparentfrom the following description, reference being had to the accompanyingdrawing, wherein a preferred form of the present invention is clearlyshown.

In the drawing:

Fig. 1 is a diagrammatic view of a refrigerah 25 ing system embodyingthe present invention;

Fig. 2 is a vertical cross section of a compre'ssor piston embodying thepresent invention and showing the valve in closed position; I

Fig. 3 is a view corresponding to Fig. 2 showing 30 the valve in partlyopen position;

Fig. 4 13 a top view ota compressor piston embodying the presentinventiomwhile Fig. 5 is a view corresponding to Fig. 4 with certain ofthe parts removed to illustrate the 35-'1J18t0h construction thereunder.

Referring now to Fig. .1, there is shown a refrige'rating systemcomprising a compressor ac having a piston i2 adapted to bereciprocated' in the usual manner in a cylinder MQA' dis- 0 charge valvei6 isiocated above the cylinder i l and communicates by a.dischsrgeconduit II with a condenser 29. lhe condenser so is connectedto a liquid refrigerant receiver 22 which is in communication. bymeansot c. conduit 24, 45 with the evaporator to which may contain theusual float valve (not shown) for regulating the expansion ofrefrigerant therein. A suction conduit 28 communicates betweentheevaporator J Hand the crankcase 2| of {the compressor ll, so and hasa branch on containing a bellows 82 forming part of a low pressurecontrol switch to for controlling I. motor I! which 'il-sdapted to drivethe compressor II by suitable driving connections (not shown). I! Thepiston 12 containsan inlet valve mecha- (m. ESQ- 229) nism for passinggaseous refrigerant from the crank. case to the compression cylinder.The inlet vaive comprises an annular valve seat 29 within which isprovided a series of passages ll communicating with the under side ofthe pis- '5' ton head. An auxiliary seat 52 is provided on the pistonhead concentric to the valve seat ii and inside the innermost portion oithe passages do. The face of the seat 42 is very slightly lower than theface of the seat 38. This feature 10 appears exaggerated in Figs. 2 and3 in order to more clearly illustrate the invention. In practice,however on a valve of the order oi an inch in diameter, the seat 62may-he approximately .004 or .005 of an inch below the seat 38 for bestresults. A valve disc M 01' a thin resil- I lent flexible material, suchas spring steel, is adapted to rest on top of the seat 38 and is biasedto close the valve by a leaf spring ii. A cover plate to is secured tothe piston head by bolts to and provides a valve chamber 52 which is incommunication with the'compression cylinder by a series of ports 54. Acentral aperture as is located in, the cover plate immediately above acorresponding central aperture 58 in the 35 valve disc I. I

In operation, gaseous refrigerant is withdrawn by the compressor fromthe evaporator 28 through the conduit 28. From the crank case, gaseousrefrigerant passes through the piston valve into the cylinder it fromwhence it is compressed and ejected through the exhaust valve it andconveyed by the conduit i8 to the condenser 20. The refrigerantliquefied in the condenser 20 is collected in the receiver 22 fromwhence it is conveyed by the conduit 24 to the evaporator 26, where thefloat valve (not shown) admits liquid, refrigerant in amounts varyingwith the rate o1 vaporization therein. The switch 84 controls operationof the motor 88 ino accordance with thepressure conditions existing intheconduit 28 and evaporator 25.

The operation of the valve shown in Figs. 2 to 5 is such that on thecompression or upward stroke of the piston, the parts lie in theposition shown in Fig. 2, wherein the valve disc II is flexed by thepressure 0! the gas in the cylinder to close both the seat 38 and theseat 42, thus preventing mic of refrigerant from the cylinder back tothe crank case. litter the como pression stroke is ended, and the pistonbegins its down stroke, the pressure diflerence between the two sides ofthe piston head is reduced to a point where the resilience of the disc44 issuillcient to permit the some to straighten'out and rise 3 from theseat M as shown in Fig. 3. This provides a very small leakage pathacross the seat t? and through the aperture 58. As soon as the pressurein the cylinder is sumciently lower than that of the crank case toovercome the spring Alt, the entire valve disc l i is raised from theseat 3% permitting free passage of gas from the crank case to thecylinder it. At the bottom of the stroke, .the pressure of the cylinderand the lo crank case are again equalized and the valve disc 35% returnsto the seat 38 while the leakage path across the seat 512 is stillmaintained open. After the piston again begins its compression stroke,the cylinder pressure increases above the i5 crank case pressure to apoint suihcient to flew. the disc 6Q into the position shown in Fig. 2wherein the leakage path across the seat 62 is again closed.

It will be seen that the provision of a small leakage immediately beforeopening of the main valve and immediately after closing thereof, tendsto cushion both the opening and closing movements of the valve in thatit prevents any sudden pressure changes between the two sides of the 2valve such as occur in ordinary valves of this general type without theadditional valve seat 62. It will he understood that while the inventionhas been illustrated as applied to a piston'valve, its advantages arelikewise useful in other epplications such as for discharge valves forcompressors and, in fact, in any, situation requiring a light, quickacting, one way valve which is not only positive and reliable in itsaction, but which must also m free from any noise in rapid operation.

While the form of embodiment of the inven tion as herein disclosed,constitutes'a preferred form, it is to be understood that other formsmight be adopted, all'coming within the scope of the claims whichfollow. What-is claimed is as follows: l. A fluid control means operatedby pressure diiierences thereon including means forming a throttlingpassage and a second passage, valve means for controlling the flow offluid through said passages, said valve means being inherently biased toown the throttling passage and to close the second passage when nopressure difierential exists, said valve means being moved by onepressure differential to close both passages and being moved by anopposite pressure differential to open both mssages, said throttlingpassage being always open when said second passage is open and. beingalso opened to permit partial equalization of pressures immediatelypreceding the opening oi the second passage.

2. A fluid control means operated by pressure differences thereonincluding means forming a throttling passage and a second passage, valvemeans for controlling the how of fluid through said passages, said valvemeans being inherently biased to open the throttling passage and toclose the second passage when no pressure differential emsts, said valvemeans being moved by one pressure differential to close both passagesand being moved by an opposite pressure differential to open bothpassages, said throttling passage having a cross-sectional area lessthan one sixteenth the area of the maximum valve opening.

3. A compressor comprising a cylinder, 9. piston therein having a fluidcontrol means comprising a plurality of valve seats located one withinthe other, one of said valve seats being slightly out of the plane ofthe other valve seat, a substantially fiat resilient disc valve adaptedto make sealing engagement first with one of the valve seats and thenwith another, said valve being provided with a throttling passageopening into 7 more than four times the area enclosed by the secondvalve seat, said disc valve being provided with a throttling orificetherein opening into the confines 'of one of said valve seats, saidthrottling orifice having an area less than one-fourth the area enclosedby the smaller valve seat, said disc valve being wholly tree of anyconnection with either of the valve seats.

WILFORD H. 'IYEETER.

